The present invention generally relates to devices which harvest fruits and vegetables from vinous plants, and more particularly to a tomato harvester having the capacity to harvest multiple rows of tomatoes in a single pass.
The ultimate objective of any harvester is to maximize the quantity of usable fruit harvested while minimizing the time and expense of bringing in the harvest. In pursuit of this objective, many different plant harvesters have been developed over the years and are known in the art. Harvesters of fruits and vegetables from vinous plants generally employ a upwardly angled ground-engaging conveyor having a plant severing or uprooting device at the lower end of the conveyor. As these harvesters travel through a field, they generally travel along a single row where they sever or uproot each entire plant in the row. The severed plants, fruit included, are conveyed upward from the ground level by assorted lifting means with which the harvester may be equipped. The severed plants and fruit are then processed through some type of separating means, such as a shaker, for separating the crop from the vine or other plant mass. One type of shaker, the drum variety, uses a drum with tines extending radially outward from the drum. Adjacent to the tines are stationary fingers or rods. The drum and tines rotate, undergoing angular acceleration and deceleration, so that the drum oscillates. The fruit-laden vines are engaged between the fingers and the tines, with the accelerating and decelerating tines stripping the fruit from the vines. The dislodged fruit generally falls through openings below the shaker, landing on another conveyor and is further processed through the harvester. Fruit which has been accepted for collection is thereafter conveyed, usually overhead, through a chute or other means into a collection vehicle traveling alongside the harvester. The remaining plant mass is moved out of the shaker, routed through the back of the harvester and dropped back onto the ground for collection or tilling.
The drum shaker has proven to be a highly effective device for separating tomatoes from the vines. Examples of harvesters using drum shakers are disclosed in U.S. Pat. Nos. 4,323,506; 4,335,570; 4,915,671; 4,927,440; 5,099,636; 5,316,519; 5,480,353; and 5,573,459.
It is desirable to harvest the fruit quickly to reduce the amount of time and manpower necessary to bring the harvested crop to the market. One means of reducing the time required for harvesting the crop is to harvest more than one row at a time. Although most machines harvest crops from a single row at a time, some dual-row machines are known for some agricultural products. For example, U.S. Pat. No. Re 34,678 (Fischer) discloses a harvester used for harvesting leafy vegetables, where the harvester has two harvesting sections arranged in side-by-side relation. The harvester disclosed in the '678 patent cuts leafy vegetables at ground level and transports the produce from the ground level to an upper position where the produce drops into receiving containers. The harvester disclosed in the '678 patent does not disclose any means for separating fruit from vegetable mass.
U.S. Pat. No. 4,965,993 (Butler) discloses a harvester specifically designed for harvesting cucumbers. This device employs two cutter assemblies, which are mounted on each side of a vehicle. The harvester disclosed in the '993 patent does not disclose the use of an oscillating drum shaker for separating the fruit from the vines, but instead employs a sharp circular edge or side edge to shear the fruit from the vine. U.S. Pat. No. 4,261,163 (Shaw) discloses a tomato harvester specifically designed to harvest tomatoes grown on plastic mulch covered beds. However, while the '163 patent discloses twin conveyors for transporting cut plants, the harvester does not separate the fruit from the vines. Instead, the cut plants, still bearing fruit, are dumped to the rear of the harvester. The cut plants are left in the field to wilt, and further processing is required to remove the fruit from the vines.
U.S. Pat. No. 4,047,573 (Cortopassi) discloses an apparatus for simultaneously harvesting two or more crop rows. A principal feature of the device disclosed in the '573 patent is the provision of dual header conveyors. Each header conveyor has a separator conveyor at its trailing end to receive vines discharged from the trailing ends of the header conveyors. From the separator conveyor, vines and attached tomatoes are transferred onto shaker conveyors. Thus, the harvester disclosed in the '573 patent does not employ a drum shaker, but instead relies on separate shaker conveyors to disengage the fruit from the vines.
Therefore, there are no known harvesters which harvest tomatoes and similar crops from multiple rows and employ drum shaker separation to separate the fruit from the vines. Several reasons may explain why such a machine, until now, has not been disclosed. First, because harvesters are frequently transported on public roads, the harvester may not exceed certain width limitations, generally a maximum of 120 inches. However, tomato rows are typically separated, from center to center, by a distance of approximately 60 to 66 inches. Therefore, a harvester capable of harvesting three rows would be expected to have ground-engaging conveyors with a combined minimum width exceeding 120 inches, which generally exceeds the width restrictions for most public roads. Second, increasing the number of rows being harvested proportionally increases the combined mass of fruit and vines which must be processed through the shaker to separate the fruit from the vines. However, increasing the capacity of the shaker by increasing the drum width in proportion to the increase in the combined mass of fruit and vines collected at the ground-engaging conveyors is impractical because of the overall width limitations previously discussed. In addition, the difficulty and cost of designing and manufacturing an extremely wide drum would be substantial because of the beam loading to which such a drum would be subjected. Therefore, a multiple row tomato harvester must not only be capable of gathering a mass of fruit and vines which may be three times or more larger than known machines, but it must also be capable of processing the increased mass with a drum shaker which is not increased in size in direct proportion to the increase in mass.
One might consider increasing the capacity of a drum shaker by simply increasing the speed, i.e., the angular velocity of the her by increasing the magnitude of the acceleration and deceleration of the drum, i.e. increasing the amplitude or frequency of the shaking mechanism. However, the fruit can be delicate, and more violent shaking is likely to damage the fruit resulting in a decrease in usable harvested fruit. In addition the capacity of the known shakers is limited by the durability and strength constraints of the shaker components.
An early version of the oscillating drum shaker is disclosed in U.S. Pat. No. 4,323,506 (Studer). In the device disclosed in the '506 patent, the severed plants are rotated underneath an oscillating tine-covered drum. The plants are shaken by subjecting them to angular acceleration and deceleration while the vines are transported around an arcuate path. A series of parallel fixed rods or bars below the drum hold the vegetative mass closely against the tines in an “envelope” area, preventing the vegetative mass from falling down or away from the drum tines. The oscillation of the drum shakes the tines and the vegetative mass, dislodging much of the fruit which falls between the rods for conveyance elsewhere. The rotation of the drum takes the vegetative mass rearward around the bottom of the drum where it is disengaged from the drum tines and then deposited on a conveyor for discard.
The '506 patent generally employs two motors to achieve the superposition of oscillatory motion on a constant angular velocity rotation. A first motor drives a main shaft at a constant angular velocity, the main shaft causing the rotation of auxiliary shafts to which are mounted eccentric weights. A second motor is mounted around but not coupled to the main shaft, the second motor having a hollow shaft. The hollow shaft is connected to the drum frame with a torsion spring, which is connected on one end to the hollow shaft and connected on the other end to a frame securing the drum. The torsion spring allows rotation and oscillation of the drum without causing damage to either the first or second motor. However, because the spring is constantly subjected to torsion, failure is inevitable. Significantly, for the harvester disclosed in the '506 patent, both the first and second motor are mounted to the outside of the torsion spring, on the same side of the drum, thereby requiring removal of both motors to replace the spring.
U.S. Pat. No. 5,316,519 (Johnson) also employs two motors to superimpose an oscillatory motion on the angular velocity rotation, however the '519 patent utilizes a different coupling mechanism to couple the drum frame and the oscillation motor. The '519 patent employs a rubber “biscuit” as a coupling, which provides a limited degree of torsional resilience between the hydraulic motor and the oscillation shaft. The problem with using elastomeric compounds for the oscillation coupling is that the couplings quickly become hot as they are subjected to repeated oscillation cycles and often fail. Unlike the '506 patent which directly drives a high speed shaft with a hydraulic motor, the '519 patent couples the weight shafts to the hydraulic motor via belt drive.
Therefore, the mounting design of the motor, or motors, and the mechanism for connecting the motor to the drum must be improved to withstand the increased loads for a multiple row harvester.
The present invention is directed toward a tomato harvester which is able to collect fruit and vines from multiple rows simultaneously, where the harvester meets standard highway width limitations and the design of the drum shaker is able to effectively process the increased mass of fruit and vines, having a coupling mechanism which is capable of withstanding greater loads and a motor design which provides for easy installation and maintenance of the motors.